Displaceable Plug in a Tool String Filter

ABSTRACT

A filter for a drill string comprises a perforated receptacle having an upper end and a lower end. The upper end of the filter comprises a drilling mud intake, and the lower end of the filter comprises an opening. A displaceable plug is seated on the opening at the lower end.

BACKGROUND OF THE INVENTION

Oil and gas well drilling operations typically require drilling mud to be circulated throughout the system. As drilling mud is recirculated during downhole drilling operations, debris from earth formations, drill bit cuttings, shavings, and other abrasive articles may damage sensitive downhole equipment. Filters used to collect the debris are known in the art. Often these filters are placed in the uppermost drill pipe of the drill string. As new pipe is added to the drill string the filter is removed, dumped out and cleaned, hoisted to the top of the derrick and placed into the newly attached uppermost pipe in the drill string.

U.S. Pat. No. 7,165,633 to Hall et al., which is herein incorporated by reference for all that it contains discloses a drilling fluid filter for placement within a bore wall of a tubular drill string component which comprises a perforated receptacle with an open end and a closed end. A hanger for engagement with the bore wall is mounted at the open end of the perforated receptacle. A mandrel is adjacent and attached to the open end of the perforated receptacle. A linkage connects the mandrel to the hanger. The linkage may be selected from the group consisting of struts, articulated struts and cams. The mandrel operates on the hanger through the linkage to engage and disengage the drilling fluid filter from the tubular drill string component. The mandrel may have a stationary portion comprising a first attachment to the open end of the perforated receptacle and a telescoping adjustable portion comprising a second attachment to the linkage. The mandrel may also comprise a top-hole interface for top-hole equipment.

U.S. Pat. No. 7,275,594 to Hall et al., which is herein incorporated by reference for all that it contains, discloses a tool string stab guide for axially aligning first tool string components with second tool string components. The stab guide has a body with an axial length along a longitudinal axis with a first and a second section. The first section of the body adapted for removable attachment within a diameter of a bore of a tool string component. The second section of the body has a centering element with a flow channel. The ratio of the axial length to the diameter is at least 2:1.

U.S. Pat. No. 7,303,029 to Hall, which is herein incorporated by reference for all it contains, discloses a filter for a drill string comprising a perforated receptacle having an open end and a perforated end and first and second mounting surfaces are adjacent to the open end. A transmission element is disposed within each of the first and second mounting surfaces. A capacitor may modify electrical characteristics of an LC circuit that comprises the transmission elements. The respective transmission elements are in communication with each other and with a transmission network integrated into the drill string. The transmission elements may be inductive couplers, direct electrical contacts, or optical couplers. In some embodiments of the present invention, the filter comprises an electronic component. The electronic component may be selected from the group consisting of a sensor, a router, a power source, a clock source, a repeater, and an amplifier.

U.S. Pat. No. 6,976,546 to Herst, which is herein incorporated by reference for all that it contains, discloses a filter system for filtering drill bit cuttings, shavings, and other abrasive articles from a drilling mud that is passed through an oil or gas well drilling system that includes an overhead drilling system, a drill string connected to the overhead drilling system, and a mud filter for filtering the drilling mud, wherein the mud filter is disposed within a drilling mud fluid passage that extends from the entry point of the drilling mud into the overhead drilling system and the entry point of the drilling mud into the drill string.

BRIEF SUMMARY OF THE INVENTION

A filter for a drill string comprises a perforated receptacle having an upper end and a lower end. The upper end of the filter comprises a drilling mud intake, and the lower end of the filter comprises an opening. A displaceable plug is seated on the opening at the lower end.

The displaceable plug may comprise a ball, a disc, or a seal. The plug may comprise a stopper proximate the lower end. A first end of a shaft may be attached to the stopper, while a second end of the shaft may extend towards the upper end of the filter. The second end of the shaft may be attached to a spider. The plug may seat within the lower end of the receptacle or on an exterior of the lower end of the receptacle. The plug may be threadably attached to the lower end of the receptacle. The plug may comprise pins receivable within grooves. These pins may be utilized to seat the plug.

The perforated receptacle may comprise a substantially conical shape. The receptacle may comprise at least one rod and a coil circumferentially disposed around the at least one rod. The receptacle may comprise perforations that are shaped as circles, squares, ovals, rectangles or other shapes. The perforated receptacle may be disposed within a saver sub or swivel. The lower end of the perforated receptacle may comprise a detachable part. A structure comprising bristles may be disposed within the filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of a downhole drill string.

FIG. 2 is a cross-sectional diagram of an embodiment of a drill pipe.

FIG. 3 a is a cross-sectional diagram of an embodiment of a filter for a drill string.

FIG. 3 b is a top-view diagram of an embodiment of a filter for a drill string.

FIG. 4 a is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 4 b is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 5 a is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 5 b is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 6 a is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 6 b is a cross-sectional diagram of another embodiment of a filter for a drill string.

FIG. 7 is a cross-sectional diagram of another embodiment of a filter for a drill string.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

Referring now to FIG. 1, a downhole drill string 101 may be suspended by a derrick 102. The drill string may comprise one or more downhole components 100, linked together in a drill string 101. The drill string 101 may be in communication with an uphole assembly 103. The uphole assembly 103 may comprise a kelly or a top-drive. The drill string 101 may comprise a saver sub 104. An upper end of the saver sub 104 may be attached to the uphole assembly 103. A lower end of the saver sub 104 may attach to the drill string. As the drill string advances into the earth additional downhole components 100 may be added to the drill string 101 at the lower end 105 of the saver sub 104.

FIG. 2 is a diagram depicting an embodiment of a drill string filter 200 disposed within a saver sub 104. The saver sub 104 may be placed intermediate an uphole assembly 103 and a drill string 101. The saver sub 104 may also be utilized as a break joint for adding new downhole components 100 as the drill string 101 advances farther into the earth. The saver sub 104 may remain in communication with the uphole assembly while new pipe is being added to the drill string.

FIG. 3 a is a diagram depicting an embodiment of a drill string filter 200. The filter 200 may comprise a perforated receptacle 310 and a displaceable plug 301. The plug 301 may comprise a stopper 302, a shaft 303, a spider 304, a through-hole 308 or various combinations thereof. When the plug 301 is seated the stopper 302 may be obstructing a port 306 in a lower end of the filter 200. A first end of the shaft 303 may be attached to the stopper 302. A second end of the shaft 303 may extend towards the upper end of the filter 200. The second end of the shaft 303 may be attached to or pass through a spider 304. The spider may comprise at least one bar 309 running perpendicular to the shaft 303. In this embodiment the spider 304 is adapted to seat on a drilling mud intake 307.

During drilling operations the filter 200 may be disposed within a saver sub. The saver sub may be attached to an uphole assembly. In some embodiments the filter may be disposed within the uphole assembly. The uphole assembly feeds drilling mud into the drill string through the saver sub and the filter 200. The filter 200 serves the purpose of removing larger particles and debris from the drilling mud. The process of filtration may lead to a build up of particles and debris within the filter 200. The removal of these particles and debris often occurs when new downhole components are added to the drill string. It is believed that the present embodiment of the filter 200 may be cleaned without requiring the physical removal of the filter from the drill string. The filter 200 may be cleaned by inserting a rod into the lower end of the filter and displacing the plug 301, allowing the buildup of particles and debris to flow around the plug 301 and out of the filter 200.

Furthermore, it is believed that by allowing the filter 200 to be cleaned from the bottom, several benefits may be gained. Firstly, in many of the present embodiments of filters that are used in the oil industry when a filter needs cleaning it must be removed from the drill string at the bottom of the derrick and then hoisted up to the top of the derrick to be inserted into the new uppermost pipe. This hoisting action creates potential for injury to the workers below the derrick as the filter is handled in the air above them. A second benefit that may be gained is that of non-interference with certain downhole telemetry systems such the one disclosed in U.S. Pat. No. 6,670,880 to Hall, which is herein incorporated by reference for all that it discloses. Present embodiments of many drill string filters have been found to interfere with the communication signals transmitted through certain drill string telemetry systems. Third, the time required to remove and reinstall a filter is expensive. The present invention may save time because the filter does not need to be removed, but may simply be emptied while still in the top hole equipment of the drill rig.

The through-hole 308 on top of the spider 304 provides an attachment point to completely remove the plug 301 from the filter if that should ever become necessary. If the filter was disposed within the saver sub then the saver sub may have to be detached from the uphole assembly to access the through-hole 308. If the filter was disposed within the uphole assembly then the uphole assembly may have to be disassembled to allow access to the through-hole 308.

FIG. 3 b depicts a top view of the embodiment of the filter shown in FIG. 3 a. The spider 304 is shown seated upon the drilling mud intake 307. The spider 304 may exert a downward force onto the rest of the plug when drilling fluid is being pumped into the filter. This downward force may act to further seat the plug.

FIG. 4 a is a depiction of another embodiment of a drill string filter 200. In this embodiment the filter 200 comprises a displaceable plug 301 in the form of a ball 401. The ball 401 is sized such that it lodges in a port 306 at the lower end of the filter 200. The filter 200 in this embodiment would also be cleaned by using a stick or pole to displace the ball 401 and allow the particles and debris to flow out.

FIG. 4 b is a depiction of another embodiment of a drill string filter 200. In this embodiment the filter 200 comprises a displaceable plug 301. The plug 301 may comprise a stopper 302, a shaft 303, a spider 304, and a through-hole 308. The shaft 303 may comprise a set of bristles 402 extending perpendicularly outward towards the inner filter wall. The bristles 402 may provide additional filtering ability. The filter 200 in the embodiment would also be cleaned by using a stick or pole to displace the plug 301 and allow the particles and debris to flow out. Additional fluid may be required to run through the filter 200 during cleaning to remove the particles and debris from the bristles 402.

FIG. 5 a is a depiction of another embodiment of a filter 200 wherein a perforated receptacle 310 has square shaped perforations 501. The perforation may be shaped in a variety of ways including but not limited to: square, circular, oval, slit, polygonal, or triangular. FIG. 5 b is a depiction of another embodiment of a filter 200. In this embodiment the perforations comprise gaps between wires 502 which have been wrapped around a set of supporting rods 503. Both of these embodiments would allow for use of any of the displaceable plugs that have previously been discussed.

FIG. 6 a is a depiction of another embodiment of a filter 200. In this embodiment the filter 200 comprises a displaceable plug 301. The displaceable plug 301 seats on an exterior of the lower end of a perforated receptacle 310. The plug may seat on the perforated receptacle through a thread form connection 601 or through a pin and groove connection. The displaceable plug may comprise a seal 602. The seal 602 may aid in keeping debris within the filter 200 during operation. In this embodiment the filter would be cleaned by removing the plug 301 from an exterior of the perforated receptacle 310. This embodiment may have the added benefit of allowing for the complete removal of the plug 301 from the filter 200. The complete removal of the plug 301 may allow for more space for the particles and debris to exit the filter 200.

FIG. 6 b is a depiction of another embodiment of a filter 200. In this embodiment the filter 200 comprises a displaceable plug 301 and a perforated receptacle 310. The lower end of the perforated receptacle 310 comprises a detachable part in the form of a keeper nut 603. The displaceable plug 301 seats within the lower end of the perforated receptacle 310 on the keeper nut 603. The keeper nut 603 may seat on an exterior of a lower end of the perforated receptacle 310. The keeper nut 603 may be in communication with the receptacle 310 through a threadform or through a pin and groove connection. This embodiment may have the added benefit of providing for a larger port 306 in the lower end of the perforated receptacle 310. If the opening provided by displacing the plug 301 did not allow adequate room for the expulsion of debris and particles then the keeper nut could be removed to increase the port 306.

FIG. 7 is a depiction of another embodiment of a filter 200. In this embodiment the filter 200 is disposed within a saver sub 104. The filter comprises a displaceable plug 301. The plug 301 may comprise a stopper 302, a shaft 303, a spider 304, and a through-hole 308. The upper end of the shaft 303 may extend above a drilling mud intake 307. The spider 304 may be attached to the upper end of the shaft 303. The spider may comprise catches 701 that interface with receivers 702 within the saver sub 104. The lower end of the shaft 303 may extend beyond the stopper 302 into a space below the filter 200. The lower end of the shaft 703 may function as a handle when cleaning the filter 200.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A filter for a drill string, the drill string comprising a plurality of drill pipes and a bottom hole assembly for drilling a borehole into the earth; the filter comprising: a perforated receptacle having an upper end and a lower end; the upper end comprising a drilling mud intake; the lower end comprising an opening; and a displaceable plug seated on the opening.
 2. The drill string filter of claim 1, wherein the displaceable plug comprises a ball.
 3. The drill string filter of claim 1, wherein the displaceable plug comprises a stopper proximate the lower end, a shaft with a first end attached to the stopper and a second end extending toward the upper end.
 4. The drill string filter of claim 3, wherein the second end is attached to a spider.
 5. The drill string filter of claim 1, wherein the perforated receptacle comprises a substantially conical shape.
 6. The drill string filter of claim 1, wherein the displaceable plug comprises a disc.
 7. The drill string filter of claim 1, where in the displaceable plug comprises a seal.
 8. The drill string filter of claim 1, wherein the perforated receptacle is disposed within a saver sub.
 9. The drill string filter of claim 1, wherein the perforated receptacle comprises circle-shaped perforations.
 10. The drill string filter of claim 1, wherein the perforated receptacle comprises square-shaped perforations.
 11. The drill string filter of claim 1, wherein the perforated receptacle comprises at least one rod and a coil circumferentially disposed around the at least one rod.
 12. The drill string filter of claim 1, wherein the displaceable plug seats within the lower end of the perforated receptacle.
 13. The drill string filter of claim 1, wherein the displaceable plug seats on an exterior of the lower end of the perforated receptacle.
 14. The drill string filter of claim 13, wherein the displaceable plug is threadably attachable to the lower end of the perforated receptacle.
 15. The drill string filter of claim 1, wherein the displaceable plug comprises pins receivable within grooves.
 16. The drill string filter of claim 1, wherein the lower end of the perforated receptacle comprises a detachable part.
 17. The drill string filter of claim 1, wherein a structure comprising bristles is disposed within the perforated receptacle. 